import java.awt.*;
import java.awt.event.*;
import javax.lang.model.element.Element;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.Caret;
import javax.swing.text.Document;

class CaesarFrame{
JFrame frame;
JTextField textField1, textField2;
JButton button;
JPanel panel1, panel2;
JComboBox<Object> comboBox1;
Object[] ob = {'A','B','C','D','E','F','G','H','I','J','K','L'
        ,'M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
Container contentPane;
JLabel label;

// Constructor
CaesarFrame(){
    frame = new JFrame("SwingLab");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 110);
    frame.setLayout(new BorderLayout());
    frame.setLocationRelativeTo(null);

    contentPane = frame.getContentPane();
    textField1 = new JTextField(20);
    textField2 = new JTextField(28);
    textField2.setEditable(false);
    button = new JButton("Code!");
    comboBox1 = new JComboBox<Object>(ob);
    label = new JLabel("Output:");
    panel1 = new JPanel();
    panel2 = new JPanel();

    panel1.add(comboBox1);
    panel1.add(textField1);
    panel1.add(button);
    panel2.add(label);
    panel2.add(textField2);

    contentPane.add(panel1, BorderLayout.NORTH);
    contentPane.add(panel2,BorderLayout.WEST);

    frame.setVisible(true);

    ActionListener buttonCode = new OkButtonActionListener();
    button.addActionListener(buttonCode);

    KeyAdapter key = new InputFieldKeyListener();
    textField1.addKeyListener(key);
    //この箇所がよくわかりません。
    KeyAdapter key2 = new InputFieldKeyListener();
    Document doc = ((DocumentEvent) key2).getDocument();
    doc.addDocumentListener((DocumentListener) key);

}

class InputFieldKeyListener extends KeyAdapter implements DocumentListener{
    public void keyTyped(KeyEvent e) {
        char temp = e.getKeyChar();
        String ch =String.valueOf(temp);
        char offset = (char) comboBox1.getSelectedItem();
        textField2.setText(Caesar.caesarCode(ch,offset));
    }

    @Override
    public void changedUpdate(DocumentEvent e) {
        System.out.println("Changed");
        }

    @Override
    public void insertUpdate(DocumentEvent e) {
        // TODO Auto-generated method stub
        System.out.println("Inserted");
        }

    @Override
    public void removeUpdate(DocumentEvent e) {
        // TODO Auto-generated method stub
        System.out.println("Removed");
        }


}



private class OkButtonActionListener implements ActionListener{
    @Override
    public void actionPerformed(ActionEvent e) {
        String message = textField1.getText();
        char offset = (char) comboBox1.getSelectedItem();
        textField2.setText(Caesar.caesarCode(message,offset));
    }
}